System and Methods for Treatment of Water Systems

ABSTRACT

A water treatment system for producing a sodium hypochlorite solution to control bacteria levels in well water containing: a pH adjuster; a container containing solid calcium hypochlorite for producing a calcium hypochlorite solution; and a container containing solid sodium carbonate for producing the sodium hypochlorite solution and a method of controlling bacteria levels in well water by using intermittent injections of a sodium hypochlorite solution with alternating pH values.

PRIORITY CLAIM

This application claims priority to U.S. Provisional Application No.61/154,840, filed Feb. 24, 2009, the contents of which are incorporatedherein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to a system and method for the treatment of watersystems. The invention more particularly relates to the control ofsubsurface bacteria associated with groundwater wells.

BACKGROUND OF THE INVENTION

The environmentally safe and economical production of clean drinkingwater continues to be a source of concern throughout the world.Typically, where the primary source of drinking water lies just underthe ground surface, wells are used to obtain the water. Typicalwellfields, whether involving single or multiple wells, are highlysusceptible to bacterial invasion during use. Bacteria causes biofoulingof the well screen and/or the well formation, decreasing wellefficiencies and creating treatment problems for the water obtained.Therefore, the periodic rehabilitation of wells is required to preventbacterial contamination.

Further, increasingly more stringent Safe Drinking Water Act regulationswill require higher levels of treatment for raw water. Also, highbacteria levels in groundwater and raw water pipelines create problemswith the more advanced treatment methods.

Conventional means of groundwater bacteria control using grossquantities of chlorine and acid based chemicals may be damaging to thewells in the long-term. Further, conventional means may also jeopardizeadvanced treatment methods, for example methods utilizing membranes.Additionally, bacteria control chemicals are typically transported andstored on site in a liquid state. Such liquid state chemicals pose anincreased the risk to the environment.

In many areas chlorine combined with naturally occurring organics in thegroundwater create carcinogenic by-products such as trihalomethanes,which poses a human health risk. Trihalomethanes are created whenorganics in the well are mixed with large amounts of sodiumhypochlorite.

The use of calcium hypochlorite alone may cause plugging of the well.

It is therefore an object of the invention to overcome the foregoingwater treatment problems. It is further an object of the invention to:

Reduce chemical usage and decrease environmental and health risks;

Increase well efficiency and reduce operational costs;

Decrease conventional well rehabilitation costs;

Support advanced treatment technologies in meeting more stringentdrinking water regulations;

Provide a unit with easy installation and minimal maintenance; and

Provide affordable bacteriologically controlled drinking water to allsize water users.

SUMMARY OF THE INVENTION

The forgoing objects and other objects are achieved by a method andsystem in accordance with the principles of the invention.

In a water treatment system in accordance with the invention a smallamount of dry chemical is used to generate a concentrated liquidsolution in an enclosed environment, thereby greatly reducingenvironmental risk. Further, the invention minimizes chemical usage andgreatly reduces trihalomethane formation during well rehabilitation.

The bacterial control unit of the present invention produces a treatmentsolution of sodium hypochlorite, which is supplied to the well water inthe well. The starting materials for making the sodium hypochlorite(NaOCl[5H₂O]) solution are dry (solid) calcium hypochlorite (Ca(OCl)₂)(lime ion) and dry (solid) sodium carbonate (Na₂CO₃) (soda ash).

Water is run into the apparatus where the pH is adjusted and thechemicals are mixed to provide the treatment solution. The treatmentsolution is intermittently injected into the well to control bacteria.

In the water treatment system of the present invention, the intake wateroptionally flows through a sediment primary filter to remove debris ifnecessary. The water then flows through the means for adjusting the pHand into a container containing dry calcium hypochlorite to form acalcium hypochlorite solution. The calcium hypochlorite solution flowsinto a container containing soda ash. The calcium hypochlorite and thesoda ash are mixed and react to form a sodium hypochlorite containingsolution. Calcium carbonate is also formed, but is unimportant to thepresent invention.

The treatment solution preferably contains at least 40% by volume sodiumhypochlorite. More preferably the treatment solution contains 40 to 50%by volume sodium hypochlorite. Preferably, the sodium hypochloritesolution also contains unreacted calcium hypochlorite. A high % (40-50%)of sodium hypochlorite is more stable than other sodium hypochloritesolutions, while retaining calcium hypochlorite (lime ion).

In an alternative form of the invention, additional calcium hypochloritesolution is mixed with the sodium hypochlorite solution prior to theinjection of the treatment solution into the well.

Where the well water to be treated is hard, the apparatus preferablycontains a means for adjusting the surface tension of water.

The treatment solution is designed to penetrate the protective sheathsurrounding the bacteria via reduced surface tension, which allows forthe use of reduced amounts of chemicals while still effectivelyoxidizing and killing the bacteria.

More preferably, the incoming water enters the apparatus and the surfacewater tension is adjusted before coming in contact with any chemicals.The pH of the water is then adjusted and the water enters the calciumhypochlorite canister.

The chemicals, calcium hypochlorite (lime ion) blended with sodiumcarbonate (soda ash) form a stable, long lasting sodium hypochloritethat preferably retains the lime ion. Lime ion retention provides moreavailable chlorine which enhances the disinfection process.

The system and method of the invention may be used on any type of wellsystem, for example, small, medium, and large wells. The amount oftreatment solution depends on the contact area of the well to betreated.

Once installed, the water treatment system can be operated manually,controlled by the water plant operators, or through a water treatmentplant telemetry system, which senses a pressure loss when the well pumpis shut off and turns the water treatment system on. The unit may beeasily maintained, for example on a monthly basis by a single fieldtechnician to vary pH level and replace chemicals as needed.

The water treatment system provides an efficient means to continuouslycontrol bacteria at the wellhead with reduced chemical usage anddecreased environmental and health risks. The unit can be operatedmanually or automatically with minimal maintenance. The unit is avehicle to prolong well life and works in concert with advancedtreatment methods to meet more stringent drinking water regulations. Theunit is an effective means of controlling bacteria by increasing wellefficiency and decreasing associated well electrical operating costs.The high cost of conventional well rehabilitation is slashed, makingbacteriologically controlled drinking water affordable to homeowners,farmers and small utilities in the United States and abroad.

The method for the treatment of water systems of the invention ispreferably used with the system of the invention.

Time of Treatment

The treatment solution may be injected into the well system any time themain well pump is shut off. The treatment should be performed on aregular, periodic basis. Treatment should be performed every 10 to 45days, depending on the condition of the well. More preferably, treatmentshould be preformed every 20 to 28 days, or on a monthly basis. Duringthe contact time (the time the treatment solution is in the well) themain well pump should be turned off. The contact time of the treatmentsolution in the well is generally about 12 hours. Preferably the contacttime is more than 6 hours. While the contact time of the treatmentsolution in the well is preferably more than 6 hours, the treatmentsolution may be injected into the well in a shorter period of time. Forexample, treatment solution may be injected into the well for a periodof one hour during each treatment.

pH of the Treatment Solution

Waterborne bacteria can become immune to oxidizing agents over time.This is why the pH adjustment manifold is an important aspect of theapparatus. On a periodic basis, the pH level of the treatment solutionis varied prior to injection into the well. Alternating the pH levelplaces the bacteria in alternating dormant and excited states. Thisinhibits bacteria growth and results in bacteria self-consumption as thestressed bacteria consume their protective sheath. This also helps tomaintain the susceptibility of the bacterial to the sodium hypochloritetreatment solution.

The means for pH control may be any means for pH control. Preferably thepH is controlled by means of a magnetic field. The electro magnetic pHadjuster or pH manifold is a device with external magnets having onepole neutralized through which the softened intake water is channeled.The pole to be neutralized depends on the desired pH range. Multipleexternal magnets may be used to control the pH level, such as systemscontaining one, two or three magnets. See FIG. 5.

The pH adjustment manifold shown in FIG. 5 contains three magnets, eachwith one pole neutralized. For example, tin or rubber may used to coverone pole of the magnet. The solution is passed through the pH adjustmentmanifold and past one, two or three of the magnets depending on the pHrange desired. FIG. 5 also illustrates how the water flow may becontrolled to adjust the number of magnets in the water flow path tocontrol the pH.

Potential hydrogen ion activity or pH is defined as the concentration ofhydrogen (H+) and the hydroxide (OH—) ions actually measured in asolution. As the concentration of hydrogen is increased and thehydroxide is decreased, the solution becomes acidic (less than 7 pH).When the hydrogen concentration is decreased and the hydroxideconcentration is increased then the solution becomes alkaline (greaterthan 7 pH). Equal ionic concentrations provides a basic solution orneutral pH of 7.

The pH manifold control valves allow the pH level to be controlled. ThepH adjusted water provides short term molecular alignment of the watermolecules within the treatment solution. This enhances disinfectingproperties.

When using magnets as the pH control means, the most important factorsare mass, gauss, and directional consistence (all magnets should beinfluencing the fluid with the same polarity).

The pH control means preferably contains magnets producing a high gaussmagnetic field. Preferably the magnets are at least 5,500 gauss. Morepreferably, pH control means contains three magnets, each about 7,000gauss.

The pH of the treatment solutions should be alternated between high(basic) and low (acid) pH solutions. It does not matter whether theinitial treatment solution is a high pH or a low pH.

The pH of the treatment solution is set depending on the type ofbacterial contamination in the well.

In general wellborn bacteria prefer a pH environment of from about 5 to7.

The pH of the treatment solution is generally set within the range of 4to 11. More preferably, the pH of the treatment solution is outside therange of 5 to 7.

Preferably the pH of the alternate treatment solutions varies by atleast three units. Preferably the pH of the acidic treatment solutionshould be below pH of about 5. More preferably, the pH of the acidictreatment solution should be pH of about 4.5. Preferably the pH of thebasic treatment solution should be above a pH of about 7. Morepreferably the pH of the basic treatment solution should be above a pHof about 8. Most preferably the pH of the basic treatment solutionshould be above a pH of about 8.5.

Preferably, the pH of the treatment solution is alternated between a pHof about 4.5 and a pH of about 8.5.

The pH may be controlled automatically or manually, for example usingfeed back from an electronic pH meter or pH paper strips.

Surface Tension Control

Where the well water to be treated is hard, the apparatus preferablycontains a means for adjusting the surface tension of water. Softeningthe water makes the treatment more effective.

The means for surface tension control may be the unit with which theintake water first comes in contact. Generally, the surface tension ofthe intake water is reduced. The means for surface tension control maybe any means for surface tension control. Preferably, the surfacetension is controlled through ionization. More preferably the surfacetension control means uses a magnetic field where the normally negativepolarity water is converted to positive polarity water. Calcium,magnesium carbonates, biocarbonates, and sulfates are kept insuspension. This produces soft water with enhanced wetabilityproperties. Water softening makes treatment more effective. Softeningthe treatment water allows penetration deep within the densebacteriological biomass by creating a cellular rupturing effect (lysing)which kills the bacteria. Softening the treatment water also decreasesthe amount of chemicals that are needed by enabling the chemicals tobecome super-saturated and pure during blending.

The magnetic field of the magnetic surface tension control meanspreferably contains magnets producing a medium gauss magnetic field.More preferably, the magnetic field of the magnetic surface tensioncontrol is about 3,500 gauss.

Bacteria

The system and method of the present invention may be used to controlnuisance or plugging bacteria commonly associated with well systems. Forexample:

Iron Bacteria

These organisms are aerobic (living or active only in the presence ofoxygen). They are found in many types of water but thrive in water whichis slightly acidic (5 to 7 pH) and contains iron. Ferrous iron isassimilated and exuded as ferrous hydroxide in the sheath surroundingthe cells. The ferrous hydroxide combines with oxygen to form ferrichydroxide. Rapid growth under certain conditions can create denseplugging deposits. The iron bacteria usually found are Clonothrix,Crenothrix, Gallionella, Leptothrix, Siderocapsa, or Sphaerotilus.

Sulfate-Reducing Bacteria

These organisms are anaerobic (living or active in the absence of freeoxygen). They often develop in water that is very low in oxygen and thatcontain sulfates and organic matter. The bacteria assimilate thesulfates and reduce them to hydrogen sulfide. Favorable water pH isbetween 5.5 and 8.5. The bacteria are minute, curved, rod-shapedorganisms, usually identified as Disulfovibrio with minor variations.

Sulfur-Bacteria

These bacteria reduce sulfides to sulfur and sometimes to sulfates. Whengrowing in the presence of hydrogen sulfide, the chain cells may containsulfur. Those most often found are Neggiatoa, thioplaca,thiospirillopsis, and thiothrix.

Slime Forming Bacteria

Direct or indirect slime formation is a property of many types ofnuisance bacteria found in well water systems. Once a film is formed,growths and absorption of suspended and colloidal materials increasesthe rate of accumulation.

The main source of food is reduced inorganic compounds. Small amounts oforganic matter present can act as a source of energy. These bacteriahave the ability to resist chemical treatments due to the protectivesheath surrounding them. They can only be treated with low surfacetension. pH ranges will differ with water quality.

Pathogenic Bacteria

For example, Pseudomonads, P. aeruginosa, Halotrophic P. (usually foundwithin iron related bacteria) Escherichia Coli and Vibrio Cholerae.

The objects, features and advantages of the invention will be apparentfrom the accompanying drawings, and from the following detaileddescription of the preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a stationary well water treatment system according tothe present invention.

FIG. 2 illustrates a portable well water treatment system according tothe present invention.

FIG. 3 illustrates the use of a stationary well water treatment systemaccording to the present invention with a submersible well pump system.

FIG. 4 illustrates the use of a stationary well water treatment systemaccording to the present invention with a vertical turbine well pumpsystem.

FIG. 5 illustrates a pH adjustment manifold useable in the presentinvention.

DETAILED DESCRIPTION

The water treatment system may be a stationary unit (FIG. 1) mounted atthe wellhead (FIGS. 3 and 4) or mobilized to the site as a portable unit(FIG. 2). The water used to prepare the treatment solution may beobtained from any water source. Usually it is most convenient to usewater directly from the well to be treated.

Referring to FIG. 1, a stationary unit 101 is shown. The stationary unitis approximately 24″×24″×15″ in size and can be easily mounted in thearea of the wellhead.

Water flows through the input line 113 to the sediment primary filter102 to remove debris. The water then flows through the surface tensioncontrol 103 which directs polarities of water molecules in one directionin order to soften the water. The water then flows through the fluidcontrol panel 104, the batch totalizer 105, the temperature gauge 106and the pH adjuster 107. The water then flows into the calciumhypochlorite (lime ion) canister 108 where a calcium hypochloritesolution is formed. The calcium hypochlorite solution then flows intothe soda ash container 109 where the calcium hypochlorite solution ismixed with soda ash to form the sodium hypochlorite treatment solution.The sodium hypochlorite treatment solution then flows out the outputline 114 to the well.

The stationary unit 101 may also contain an air vent check valve 110 toevacuate air from the system and an indicator light 111 to show when theunit is operating. A flow meter 112 shows the rate of water flow and thebatch totalizer 105 keeps track of the volume of water that has flowedthrough the system.

Referring to FIG. 2, a portable unit 201 is shown. Water flows throughthe sediment primary filter 202 to remove debris. The water then flowsthrough the surface tension control 203 which directs polarities ofwater molecules in one direction in order to soften the water. The waterthen flows through the fluid control panel 204, the pressure gauge 221,the batch totalizer 205, the temperature gauge 206 and the pH adjuster207. The water then flows into the calcium hypochlorite (lime ion)canister 208 where a calcium hypochlorite solution is formed.

When the fluid fills to a preset level, the calcium hypochloritesolution triggers a pump switch 213 and the solution flows through thepump switch and down to the float switch 222 and is then pumped throughthe mixing jet 214 to the mixing tank 209, which contains sodiumcarbonate (soda ash). In the mixing tank 209 a sodium hypochloritesolution is formed.

The pump switch also pumps the sodium hypochlorite solution down to theoutlet line 215 of the mixing tank 209 to an outlet line 216 of calciumhypochlorite canister 208 where the hypochlorite treatment solution andadditional calcium hypochlorite solution are mixed to form the sodiumhypochlorite treatment solution.

Finally, the sodium hypochlorite solution with the retained calciumhypochlorite (lime ion) are pumped via a pump 217 through the hose reel218 to the well.

By-pass lines 219 are located on the calcium hypochlorite canister andthe float switch, respectively, for preventing overflow. A wash downhose 220 is attached to the apparatus for cleaning the water treatmentsystem.

Referring to FIG. 3 the stationary system 101 is attached to submersiblewell pump system that uses a submersible well pump.

Referring to FIG. 4 the stationary system 101 is attached to well pumpsystem that uses a vertical turbine pump.

FIG. 5 illustrates a pH adjustment manifold 501 useable in the presentinvention. Three magnets are connected in series. The valves controlwater flow so that water flows through none, one, two, and/or three ofthe magnets, depending on the pH requirements desired.

The effect of the variation in pH of the present method is shown in thefollowing test example. The supply water of the test example exhibitedsignificant bacteria activity levels, indicating the potential forbiofouling downstream treatment systems and biological regrowth withinthe well pump system and pipelines.

At monthly intervals (30-day cyclical injections), the well was treatedwith 250 gallons of a sodium hypochlorite treatment solution with pH asshown in Table 1. The contact area was a 3150 gallon plume with an eighthour contact time.

TABLE 1 First Month (1st injection) 4.5 pH Second Month (2nd injection)8.5 pH Third Month (3rd injection) 4.5 pH Fourth Month (4th injection)8.5 pH

No residual chemicals were recorded at the end of the total contact timeand the pH returned to the original 6.9. The composite bacteriologicalresults are shown in Table 2. Table 2 show the results of average logheterotropic plate counts (colony forming units (CFU) per ml.

TABLE 2 First Month 4.20 CFU/ml Second Month 3.86 CFU/ml Third Month2.73 CFU/ml Fourth Month 1.32 CFU/ml

As seen from the results of Table 2, the method using pH control of thepresent invention is effective in controlling bacteria activity levelsin well water systems.

1. A water treatment system for producing a sodium hypochlorite solution to control bacteria levels in well water, comprising: a line for inputting water; a pH adjuster, in fluid communication with said line, for adjusting a pH of the input water; a container containing solid calcium hypochlorite, in fluid communication with said pH adjuster, for producing a calcium hypochlorite solution; a container containing solid sodium carbonate, in fluid communication with said container containing calcium hypochlorite, for producing a sodium hypochlorite solution; and a line, in fluid communication with said container containing sodium carbonate, for supplying the produced sodium hypochlorite solution to the well.
 2. The water treatment system of claim 1, wherein the pH adjuster is an electromagnetic pH adjuster.
 3. The water treatment system of claim 2, wherein the electro-magnetic pH adjuster comprises at least one pole neutralized magnet.
 4. The water treatment system of claim 2, wherein the magnetic field of said at least one magnet is in the range of about 1250 to 1350 gauss.
 5. The water treatment system of claim 1, further comprising a surface tension control means for ionizing the input water to reduce surface tension of the input water.
 6. The water treatment system of claim 5, wherein the surface tension control means ionizes the input water using a magnetic field.
 7. The water treatment system of claim 6, wherein the magnetic field is about 7500 gauss.
 8. The water treatment system of claim 1, further comprising a sediment filter.
 9. The water treatment system of claim 1, further comprising a flow control panel and a flow meter for regulating an amount of the input water.
 10. The water treatment system of claim 1, further comprising a line from said calcium hypochlorite container to said line for supplying the produced sodium hypochlorite solution to the well.
 11. The water treatment system of claim 10, further comprising by-pass lines, located on the calcium hypochlorite canister and the float switch, for preventing overflow.
 12. The water treatment system of claim 1, wherein the water treatment system is portable.
 13. The water treatment system of claim 1, wherein the water treatment system is fixed at the site of the well.
 14. A method for controlling bacteria levels in well water, comprising: (a) producing a first sodium hypochlorite solution having a first pH using the water treatment system of claim 1, said first pH being different than a pH of the well water; (b) supplying said first sodium hypochlorite solution to the well water; (c) producing a second sodium hypochlorite solution having a second pH using the water treatment system of claim 1, said second pH being different than the pH of the well water; (d) supplying the second sodium hypochlorite solution to the well water; and (e) repeating steps (b) through (d); whereby the bacterial content in the well water is reduced.
 15. The method of claim 14, wherein said first and second sodium hypochlorite solutions are produced using well water.
 16. The method of claim 15, further comprising reducing the surface tension of the well water.
 17. The method of claim 14, wherein said first pH and said second pH are between 4 and
 11. 18. The method of claim 14, wherein said first pH is acidic and said second pH is basic.
 19. The method of claim 14, wherein said first pH is basic and said second pH is acidic.
 20. The method of claim 14, wherein one of said first pH and said second pH is below a pH of about 5 and the other is above a pH of about
 7. 21. The method of claim 14, wherein one of said first pH and said second pH is a pH of about 4.5 and the other is a pH of about 8.5.
 22. The method of claim 14, wherein said second sodium hypochlorite solution is supplied to said well 10 to 45 days after said first sodium hypochlorite solution is supplied to said well.
 23. The method of claim 14, wherein said second sodium hypochlorite solution is supplied to said well about one month after said first sodium hypochlorite solution is supplied to said well.
 24. The method of claim 14, wherein said first sodium hypochlorite solution and said second sodium hypochlorite solution comprise 40-50% by volume sodium hypochlorite.
 25. The method of claim 14, wherein said first sodium hypochlorite solution and said second sodium hypochlorite solution comprise calcium hypochlorite.
 26. A method for controlling bacteria levels in well water, comprising the steps of: (a) producing a first sodium hypochlorite solution having a first pH, said first pH being different than a pH of the well water; (b) supplying said first sodium hypochlorite solution to the well water; (c) producing a second sodium hypochlorite solution having a second pH, said second pH being different than the pH of the well water; (d) supplying the second sodium hypochlorite solution to the well water; and (e) repeating steps (c) through (d); whereby bacteria content in the well water are reduced.
 27. The method of claim 26, wherein said first pH and said second pH are between 4 and
 11. 28. The method of claim 26, wherein said first pH is acidic and said second pH is basic.
 29. The method of claim 26, wherein said first pH is basic and said second pH is acidic.
 30. The method of claim 26, wherein one of said first pH and said second pH is below a pH of about 5 and the other is above a pH of about
 7. 31. The method of claim 26, wherein one of said first pH and said second pH is a pH of about 4.5 and the other is a pH of about 8.5.
 32. The method of claim 26, wherein said second sodium hypochlorite solution is supplied to said well 10 to 45 days after said first sodium hypochlorite solution is supplied to said well.
 33. The method of claim 26, wherein said second sodium hypochlorite solution is supplied to said well about one month after said first sodium hypochlorite solution is supplied to said well.
 34. The method of claim 26, wherein said first sodium hypochlorite solution and said second sodium hypochlorite solution comprise 40-50% by volume sodium hypochlorite.
 35. The method of claim 26, wherein said first sodium hypochlorite solution and said second sodium hypochlorite solution comprise calcium hypochlorite. 